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A californium neutron flux multiplier (CFX) is a source of neutrons for research purposes. It contains a small amount of californium-252 and several plates of highly enriched uranium (uranium-235) in a subcritical configuration. As the californium undergoes spontaneous nuclear decay, it
Some isotopes undergo spontaneous fission (SF) with emission of neutrons.The most common spontaneous fission source is the isotope californium-252. 252 Cf and all other SF neutron sources are made by irradiating uranium or a transuranic element in a nuclear reactor, where neutrons are absorbed in the starting material and its subsequent reaction products, transmuting the starting material into ...
Neutron moisture gauges use 252 Cf to find water and petroleum layers in oil wells, as a portable neutron source for gold and silver prospecting for on-the-spot analysis, [21] and to detect ground water movement. [65] The main uses of 252 Cf in 1982 were, reactor start-up (48.3%), fuel rod scanning (25.3%), and activation analysis (19.4%). [66]
Californium-252 production diagram Californium-252 (Cf-252, 252 Cf) undergoes spontaneous fission with a branching ratio of 3.09% and is used in small neutron sources . Fission neutrons have an energy range of 0 to 13 MeV with a mean value of 2.3 MeV and a most probable value of 1 MeV.
Pu-239 is produced artificially in nuclear reactors when a neutron is absorbed by U-238, forming U-239, which then decays in a rapid two-step process into Pu-239. [22] It can then be separated from the uranium in a nuclear reprocessing plant. [23] Weapons-grade plutonium is defined as being predominantly Pu-239, typically about 93% Pu-239. [24]
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The probability of such events increases with the neutron flux, and nuclear explosions are the most powerful man-made neutron sources, providing densities of the order 10 23 neutrons/cm 2 within a microsecond, or about 10 29 neutrons/(cm 2 ·s). In comparison, the flux of HFIR is 5 × 10 15 neutrons/(cm 2 ·s).